Research project: Corrosion Control for Naval Ships

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As part of the European Defence Agency project ‘Corrosion Control for Naval Ships', Southampton is tasked to develop smart corrosion protection for marine structures using multifunctional coating systems. This innovative approach aims to detect, locate, and characterise the damage in addition to providing long-term self-healing protection.

Project Overview

The proper function of seawater piping systems is of great importance for the correct operation of any ship. Seawater piping systems do not only include pipes but also the water inlet and outlet, the sea chest, heat exchangers and other systems being operated with sea water.

Considering material protection, seawater has two characteristics which have to be taken into account. First, seawater contains a considerable amount of solved salts, especially chlorides. Chlorides always favour corrosion and they may destroy the oxide layer on passive materials and thus also make corrosion resistant materials corrode. Second, a lot of species from microorganisms to barnacles and mussels living in seawater may colonize the seawater piping system of a ship (biofouling development). The first stage of development of this biological process is the growth of biofilms. This film may slow down flow rates or plug filter elements. Biofilms may significantly reduce the heat transfer efficiency in seawater operated heat exchangers. These organisms create harmful metabolites and so form specific conditions at the interface between material and sea water. In this way, they favour special types of corrosion especially on passive materials. Also, barnacles and mussels may physically block piping systems.

Atomic force microscopy

The purpose of this work is to assess the limits and drawbacks of existing technologies for biofilm control and to improve them. As most of the piping systems on board of ships and submarines are made of copper - nickel alloys these alloys will be in the focus of interest. Based on the existing experience of the partners and a comprehensive literature review, a test matrix will include the conditions present on-board a ship and a variation of the parameters such as flow velocity, pH, water temperature and conductivity.

All these issues related to the corrosion and fouling of seawater piping systems will be experimentally tested in test rigs in different facilities of the partners.

Improving the performance of organic coatings: Using the right coatings for the protection and the prevention of corrosion on steel structures on ships is important from both the viewpoint of maintenance and repair time and costs, as well as environmental impact. Current practice for painting and repair will require the use of materials that have been chosen and qualified for use to specific standards that have been laid down by either the customer or the relevant governmental organisation. It may be, therefore, that the current range of products being used for the protection of structures and prevention of corrosion are not the best for purpose of the most environmentally point of view.